In message , Mark Brader
writes
You never could, without some external knowledge. Here's a bus:

http://www.greggayden.com/europe05/London%20Bus.jpg

You want Piccadilly Circus, but you a tourist unfamiliar with London.
Is this bus going there, or has it passed there already?
I do take that point Mark and the old system wasn't perfect in that
respect of course. However, it does give people with some knowledge of
London a rough guide to which general route a bus is on. For example,
will this bus be heading from Strand up regent Street to oxford Street?
Or would it go off down Whitehall to Westminster? Or how about
straight on along Piccadilly and towards Knightsbridge?

Of course, it's different if you do have an idea of the order of the
various places and where you are in relation to them. Then the list of
places may indeed be useful.
Indeed.
--
Ian Jelf, MITG
Birmingham, UK

Registered Blue Badge Tourist Guide for London and the Heart of England
http://www.bluebadge.demon.co.uk